Here is a site that will answer just about any question anybody has about allergies. Yeah, I work at an allergist office. Like most have said, allergies to pollens, dust, and dust mites are unavoidable. There is no way to make them disappear, you just have to decrease your exposure by HEPA filter air filters, frequent washing of linens, changing your furnace filters frequently, vacuuming more often and modify your gardening practices and the list can go on......
Here is the site:
http://www.aaaai.org/